FLOOD10395 ‎(2)‎

• County: Montezuma
• Community: Dolores
• Stream Name: Dolores River
• Title: Dolores River near Dolores, Colorado, Flood Insurance Study
• Date: 5/1/2004
• Prepared For: Dolores
• Prepared By: US Army Corps of Engineers
• Floodplain - Doc Type: Floodplain Report/Masterplan

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Table 1
Average Monthly Temperature COF)
Dolores River Basin above Dolores, Colorado
Station Name Cortez Dolores Mancos Rico Silverton Telluride
Elevation (ft) 6153 6936 7030 8827 9278 8792
Jan 26.6 26.6 25.9 18.6 13.9 19.8
Feb 31.9 31.6 30.5 22.3 17.0 23.6
Mar 38.9 38.3 37.0 28.5 23.3 29.6
Apr 45.6 45.1 44.0 35.9 30.7 37.0
May 54.5 54.1 52.9 45.2 40.9 46.2
Jun 64.4 64.0 62.8 53.8 49.1 54.8
Jul 70.8 70.2 68.6 . 59.0 54.5 59.6
Aug 69.1 68.5 66.9 57.6 53.0 58.4
Sep 61.2 60.8 59.5 50.8 46.5 51.6
Oct 49.7 49.4 48.4 41.1 37.1 41.8
Nov 37.0 36.7 35.6 28.0 23.8 28.8
Dec 28.5 28.4 27.7 19.9 15.0 21.0
Average
Annual 48.2 47.8 46.7 38.4 33.7 39.4
Temperature

Source: City-Data. Com website http://www.city-data.com/city/Colorado.html

5.5 Precipitation. The Normal Annual Precipitation (NAP) at stations located in and

adjoining the upper Dolores River basin varies from a high of 24 inches at Silverton to a

minimum of around 12 inches at Pleasant View. The NAP at Dolores is 18.5 inches. The

maximum annual observed precipitation in or adjoining the Dolores basin was 41.5 inches at

Silverton in 1911; the minimum annual precipitation near the Dolores Drainage Basin was 5.5

inches, recorded at Pleasant View during the drought of 1976-1977. The Basin Normal Average

Precipitation (BNAP) for the Dolores River basin above Dolores is 28.8 inches, based on the 30-

year record 1961-1990. Local precipitation records and a regional isohyetal map developed by

Oregon State University were used to calculate the BNAP (Reference 4-q). Table 2 lists station

maximum, minimum, and average annual precipitation and Plate 4 shows the basin normal annual

precipitation isohyetal map and its gage locations.

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